This invention relates generally to interior trim panels for motor vehicles and more particularly to interior trim panels that have a discrete air bag door that is opened by an air bag when it is deployed into the passenger compartment.
U.S. Pat. No. 4,893,833 granted to Anthony J. DiSalvo and David J. Bauer Jan. 16, 1990 discloses a closure arrangement for an air bag deployment opening in an automotive instrument panel that includes a discrete door. The door has an inner supporting layer of aluminum that has a hinging extension at one end that is bolted to a structural support plate underlying the instrument panel. The opposite end of the door is held down by a frangible tab of the door covering that is beneath a lip of the structural support plate of the instrument panel. In a second version, the door has an inner supporting layer of molded plastic that includes an integral hinging flange near one end that is fastened to the air bag canister. The plastic supporting layer of the door also has an integral frangible flange near the opposite end for holding the opposite end of the door down.
U.S. Pat. No. 4,925,209 granted to Hideyki Sakurai May 15, 1990 discloses an assembly for mounting a discrete air bag door having an aluminum insert formed integrally with the air bag door. The aluminum insert has a hinging extension at an upper end of the door that has bolt holes and a folded outer edge that is wrapped around a reinforcing rod. The door is attached to the air bag canister by bolts inserted into the boltholes and the reinforcing rod keeps the door attached in case the insert cracks at the boltholes. The lower end of the door is held down by bolts that extend through cut-outs in the lower end of the cover covering to clamp the lower end of the door covering between a resilient member and a flange of the air bag canister.
U.S. Pat. No. 5,096,221 granted to Richard Coombs and Scott Rafferty Mar. 17, 1992 discloses an interior trim panel for a motor vehicle having a discrete air bag door with two substrates. The second substrate is riveted to the first substrate to reinforce the door. The second substrate has extensions at each end which define a hinged connection at one end of the door and a releasable connection at the opposite end of the door which are attached to flanges of the reinforcing insert of the interior trim panel for holding the door in place until the air bag is deployed.
U.S. Pat. No. 5,116,079 granted to Richard D. Rhodes, Jr. May 26, 1992 discloses an automotive instrument panel having an integrated air bag door. The lower end of the door skin carries a depending flap that is sewn to an inwardly extending flap of the dashboard skin to hold the lower end of the door down. The line of stitching forms a frangible tear seam line.
U.S. Pat. No. 5,238,264 granted to William J. Barnes Aug. 24, 1993 discloses a deployment door for an air bag in which the air bag door comprises a substrate panel that is attached to the substrate of the instrument panel by a Z-shaped hinge strap. The substrate panel has a row of apertures to weaken the door. During deployment the hinge strap which defines a primary hinge axis progressively unfolds and bends while the row of apertures which define a secondary hinge axis allow bending and folding of the door as shown in FIG. 1 of the patent.
U.S. Pat. No. 5,362,096 granted Nov. 8, 1994 to Satoh et al. discloses a metal deployment door for an air bag with a weakened hinge formed by holes and a rivet connection.
U.S. Pat. No. 5,419,583 granted May 30, 1995 to Sakakida et al. discloses a door cover configured to absorb passenger impact forces by yielding under any such impact.
U.S. Pat. No. 5,374,078 granted Dec. 20, 1994 to Amamori et al. discloses a hinge-reinforcing bracket that helps locate a bending hinge point in an air bag deployment door.
U.S. Pat. No. 5,437,470 granted Aug. 1, 1995 to Terai et al. also discloses such a hinge-reinforcing bracket with a V-shaped cross-section.
While each of the above air bag door arrangements may be useful for their intended purposes, there is still room for improvement particularly with respect to the attachment of discrete air bag doors to interior trim panels for motor vehicles, such as instrument panels.